Lithium metal and its various compounds are finding increasing commercial applications in the production of: lubricating greases; glass and ceramics; aluminum; in swimming pool sanitizers; air conditioning and refrigeration systems; primary and secondary batteries; nuclear energy production; and even in drugs for the control of manic-depressive psychosis. Most of these uses require lithium compounds of high quality.
Natural brines have long been recognized as a potential source of lithium values and much work has been done with varying degrees of success in attempts to commercialize such resources. Such brines, however, generally contain only very small amounts of lithium. For example, the brines of the Great Salt Lake in Utah contain only about 34 to 66 ppm. Other natural brines such as those derived from ground water in mines or other sources may contain up to about 0.5% lithium but such concentrated brines are rare. Also, many of these brines are associated with high concentrations of magnesium which makes lithium recovery uneconomical. Therefore, the recovery of lithium from natural brines presents a very difficult task, not only because of the economics of working with the very low concentrations of lithium which occur in nature, but also due to the difficulty of separating lithium compounds in a useful degree of purity from the closely chemically related materials with which lithium salts are normally contaminated. Nevertheless, the demand for lithium is such that various attempts have been made in the prior art to recover the lithium values of natural brines.